Search found 190 matches

by parallax
Tue Mar 11, 2008 2:45 am UTC
Forum: Science
Topic: Photon moving directly away from black hole?
Replies: 33
Views: 2929

Re: Photon moving directly away from black hole?

Depending on how you want to define your terms, either: the photon is moving directly "away" from the singularity, but space-time is being dragged underneath it at a rate faster than the speed of light (Imagine running away from the singularity at 10 MPH on a long treadmill or moving sidew...
by parallax
Mon Mar 10, 2008 5:57 pm UTC
Forum: Mathematics
Topic: Finding standard deviation with only a single data point...
Replies: 14
Views: 12032

Re: Finding standard deviation with only a single data point...

You can't calculate a standard deviation using only one data point, because then there is no deviation. You need to get the mean and standard deviation from another source.
by parallax
Fri Mar 07, 2008 5:57 pm UTC
Forum: Science
Topic: Quantum Mechanics, Delta Function Potential
Replies: 3
Views: 1381

Re: Quantum Mechanics, Delta Function Potential

I would suggest working the problem out with positive and negative Gaussian or rectangular potentials and compare the limits as the width -> 0. This will give you an idea of what is happening.
by parallax
Tue Mar 04, 2008 2:12 am UTC
Forum: Forum Games
Topic: Mornington Crescent
Replies: 2713
Views: 285816

Re: Mornington Crescent

Knightsbridge to Dollis Hill . Argg, I was going to play Ongar. Now my development has been set back significantly. I guess that's what I get for leading with Aldwych. Edie Bjorlin actually solved the Brixton cycle problem in 1992 using an exhaustive computer search. Proper play by three coordinated...
by parallax
Fri Feb 29, 2008 1:48 am UTC
Forum: Forum Games
Topic: Mornington Crescent
Replies: 2713
Views: 285816

Re: Mornington Crescent

Are we adopting the ten-move rule in this game? I know that it's not quite Tudor Court-standard, but most people add it anyway. I'd suggest that we do. Tudor Court games tend to be biased toward the southern quadrant if they don't include it. I'll make a triple-pass to Knightsbridge , rounding the ...
by parallax
Thu Feb 28, 2008 6:24 pm UTC
Forum: General
Topic: Sleep-time holodeck experiences
Replies: 3408
Views: 797510

Re: What were your dreams last night?

The dream starts out as being part of a fighting game, where I'm Ryu or someone similar. Then, I play against this guy, but he doesn't fight back and just asks me to beat him. Then, another guy takes the sword and shield and gives it to this general guy, with a large army. He tells him that it is th...
by parallax
Thu Feb 28, 2008 6:03 pm UTC
Forum: Forum Games
Topic: Mornington Crescent
Replies: 2713
Views: 285816

Re: Mornington Crescent

Seems this game will require a more aggressive strategy. I'll open with Aldwych. I know most consider this a calamitous opening move, but the German literature proves that it is sound. See the Hamburg games from 1982 for some examples that led to strong positional play from that station.
by parallax
Thu Feb 28, 2008 7:08 am UTC
Forum: Forum Games
Topic: Change an Acronym
Replies: 227
Views: 24834

Re: Change an Acronym

Xenon Radio-Display

NAMBLA
by parallax
Thu Feb 28, 2008 5:50 am UTC
Forum: Forum Games
Topic: 3 letters in a word
Replies: 1802
Views: 286360

Re: 3 letters in a word

roughrider

lfm
by parallax
Thu Feb 28, 2008 5:43 am UTC
Forum: Forum Games
Topic: The Game
Replies: 58
Views: 5824

Re: The Game

If I lose, and no one is around to hear me say it, does it still count? </philosophical query>

If you had anterograde amnesia, you would probably never lose twenty dollars and my self respect.
by parallax
Thu Feb 28, 2008 5:18 am UTC
Forum: Forum Games
Topic: Mornington Crescent
Replies: 2713
Views: 285816

Re: Mornington Crescent

In a game with as many players popping in and out as this one, a merger's almost always a good idea. At least, that's my experience. Depends on the merger type. The Munich merger, for example, is often disastrous. Well, mergers are always high-risk, high-reward maneuvers. Anyway, I'll play to Marbl...
by parallax
Tue Feb 26, 2008 4:45 am UTC
Forum: Science
Topic: How will these gases be distributed?
Replies: 17
Views: 2173

Re: How will these gases be distributed?

The problem can be modeled with a system of differential equations. Let f α n (t) be the number of particles of color α in bulb n. Let A α mn be the probability of a particle moving from bulb m to bulb n. Assume an ideal gas (the particles do not collide or interact with each other). df α n /dt = Σ ...
by parallax
Fri Feb 22, 2008 8:23 am UTC
Forum: Science
Topic: Cosmology Is Killing Me!!
Replies: 7
Views: 1450

Re: Cosmology Is Killing Me!!

I'm not aware of any big bang models that involve a "before matter/mass". Gravity is fundamental to the big bang.
by parallax
Fri Feb 22, 2008 3:25 am UTC
Forum: Science
Topic: The Earth Is 6,000 Years Old
Replies: 146
Views: 18746

Re: The Earth Is 6,000 Years Old

The sun uses 5,000,000 tonnes of hydrogen every single second. This would mean the Sun consumes the mass of the Earth in about 70,000 years. Dr. Louis Barbier, on NASA.gov If you take this completely out of context . . . The lunar dust is discussed in the link Sir_Elderberry gave. His comet argumen...
by parallax
Thu Feb 21, 2008 4:48 am UTC
Forum: News & Articles
Topic: Romance and Math - BBC News
Replies: 9
Views: 1992

Re: Romance and Math - BBC News

The Heisenberg Uncertainty Principle states that it is impossible to tell whether a specific misuse of the Heisenberg Uncertainty Principle will irritate me or amuse me until I read it.
by parallax
Thu Feb 21, 2008 3:47 am UTC
Forum: Mathematics
Topic: Lil' maths puzzle .....
Replies: 14
Views: 1941

Re: Lil' maths puzzle .....

Anybody know how to solve B x C = B^C plzzz ?? The previous poster already started this for you: The first step would obviously be to notice that (A^B)^C = A^(B*C). Since |A| is not 1 or 0, this shows that (A^B)^C = A^(B^C) if and only if B*C = B^C. If B != 0, this means C = B^(C-1), and thus if C ...
by parallax
Thu Feb 21, 2008 3:31 am UTC
Forum: Science
Topic: Cosmology Is Killing Me!!
Replies: 7
Views: 1450

Re: Cosmology Is Killing Me!!

The effects of a gravitational wave are qualitatively different than the effects of normal gravity. See the animations on the wikipedia page for more details.
by parallax
Thu Feb 21, 2008 3:25 am UTC
Forum: Science
Topic: Sister Particles Experiment
Replies: 11
Views: 2292

Re: Sister Particles Experiment

Quantum Entanglement Paradox Explained: Imagine we have a box with three numbered compartments, with a special lock so that only one compartment may be opened. Once one is opened, the other two compartments are permanently sealed. Whenever a compartment is opened, there will either be a red ball or ...
by parallax
Wed Feb 20, 2008 1:40 pm UTC
Forum: Science
Topic: Sister Particles Experiment
Replies: 11
Views: 2292

Re: Sister Particles Experiment

One of the particles was spun, while the other was observed, and the second particle began spinning instantaneously in the opposite direction. This is the offending statement. If this were true, it would be possible to send information. What really happens is this: The spin of one of the particles ...
by parallax
Wed Feb 20, 2008 1:33 pm UTC
Forum: Science
Topic: Only a Theory
Replies: 39
Views: 6436

Re: Only a Theory

ArmonSore wrote:How is gravity a theory? It's an observable physical phenomena!


What I don't understand is why people don't think evolution is an observable physical phenomena. The fossil record is fairly impressive in this regard.
by parallax
Sat Feb 16, 2008 7:19 pm UTC
Forum: Language/Linguistics
Topic: Portmanteaux
Replies: 124
Views: 18238

Re: Portmanteaux

I'm fond of referring to Arnold Schwarzenegger as The Governator. "You will be Governed." Then, when his re-election comes up, "I'll be back."
by parallax
Sat Feb 16, 2008 7:08 pm UTC
Forum: Language/Linguistics
Topic: Annoying words, and Words You Hate
Replies: 1994
Views: 495120

Re: Annoying words, and Words You Hate

mrbaggins wrote:Wait, epitome ISN'T EPIsode and TOME?

I'm being serious here.... how is it supposed to sound?

Moist doesn't bother me at all... although I know a few people it does bother.


eh - pit - oh - mee

Stress on the bold syllable.
by parallax
Sat Feb 16, 2008 5:58 pm UTC
Forum: Music
Topic: Songs From the 80s!?!?!
Replies: 46
Views: 8408

Re: Songs From the 80s!?!?!

SomeoneElse wrote:Its the final countdooown!


Glad someone else is with me on this one. It has the greatest synth line ever synthesized.
by parallax
Sat Feb 16, 2008 4:05 pm UTC
Forum: Mathematics
Topic: Philosophical Justification of Indeterminate Forms
Replies: 35
Views: 4128

Re: Philosophical Justification of Indeterminate Forms

Indeterminate forms are pretty easy to justify, actually. For example:

1 - 1x is always 1, but x is always 0 or ∞. So, the combined form is indeterminate.

0∞ - 0 times anything is 0. ∞ "times" anything is ∞. So, 0∞ is indeterminate.
by parallax
Wed Feb 06, 2008 7:31 am UTC
Forum: Science
Topic: G Force
Replies: 11
Views: 1713

Re: G Force

Actually, OP asked for the "G Force", which is frequently given in multiples of Earth's gravitational force at the surface. So the correct answer to his query is 0.86 Gs or 86% Earth gravity. As this quantity is a ratio, it doesn't matter whether you use acceleration or force. Not sure whe...
by parallax
Wed Feb 06, 2008 3:51 am UTC
Forum: Science
Topic: G Force
Replies: 11
Views: 1713

Re: G Force

His equation is fine.

a = G mE/rorbit2 = (rE/rorbit)2 * G mE/rE2 = (rE/rorbit)2 * g

Which is (6.37/6.87)2*(9.8 ) = 8.43 ms-2.
by parallax
Fri Feb 01, 2008 5:14 am UTC
Forum: General
Topic: Beliefs That You Cannot Prove
Replies: 123
Views: 9642

Re: Beliefs That You Cannot Prove

I believe in the unprovable assertion that the universe behaves according to rules that we are able to understand, even though we haven't discovered all of them yet. And for some reason, I also believe that one day we will discover them all, even though every generation of scientists before us has c...
by parallax
Thu Jan 31, 2008 7:26 pm UTC
Forum: Mathematics
Topic: random element from a set of unknown (finite) cardinality
Replies: 23
Views: 2401

Re: random element from a set of unknown (finite) cardinality

My point is that, given this algorithm, it would be possible to generate a uniform random integer if only you had a machine capable of performing supertasks . There is no logical reason why you would be unable to do so. Yes, the probability of choosing any particular integer is zero; that does not ...
by parallax
Thu Jan 31, 2008 5:21 am UTC
Forum: Mathematics
Topic: random element from a set of unknown (finite) cardinality
Replies: 23
Views: 2401

Re: random element from a set of unknown (finite) cardinality

My point is that, given this algorithm, it would be possible to generate a uniform random integer if only you had a machine capable of performing supertasks . There is no logical reason why you would be unable to do so. Yes, the probability of choosing any particular integer is zero; that does not m...
by parallax
Wed Jan 30, 2008 9:41 am UTC
Forum: Mathematics
Topic: random element from a set of unknown (finite) cardinality
Replies: 23
Views: 2401

Re: random element from a set of unknown (finite) cardinality

I think the best use for this algorithm is to pick a number from the set of all natural numbers with uniform probability. Sure, it requires an infinite number of steps, but no one's ever let that stop them before, has it?
by parallax
Wed Jan 30, 2008 4:18 am UTC
Forum: Science
Topic: Artificial gravity through superconductors
Replies: 19
Views: 2390

Re: Artificial gravity through superconductors

It should be noted that you don't gave to produce gravity equivalent to the entire Earth's mass because your center of gravity will be less than one Earth radius away from the deck. So, Econductor = mEc2(hdeck/rE)2 which is on the order of 1030J.
by parallax
Tue Jan 15, 2008 2:36 am UTC
Forum: Science
Topic: Significant Figures in Chemistry
Replies: 3
Views: 1215

Re: Significant Figures in Chemistry

There is no measurement error associated with 6 molecules. It's not 6.00023 molecules or 5.99982 molecules, it's 6.0000 molecules exactly. The same applies to defined constants such as the number of seconds in a minute.
by parallax
Mon Oct 29, 2007 6:11 pm UTC
Forum: Mathematics
Topic: (anything)^0?
Replies: 30
Views: 5180

Re: (anything)^0?

a^(b+c) = a^b * a^c does not hold for a=0. Otherwise, 0 = 0^1 = 0^(2-1) = 0^2 / 0^1 = 0/0.

0^0 != 0/0.
by parallax
Fri Oct 26, 2007 5:10 pm UTC
Forum: Mathematics
Topic: (anything)^0?
Replies: 30
Views: 5180

Re: (anything)^0?

0^0 is usually 1, but when taking limits, it is an indeterminate form. That's because x^0 = 1, but 0^x = 0. So the value of the limit x^y depends on how fast x and y go to 0 relative to each other.
by parallax
Thu Sep 20, 2007 3:19 am UTC
Forum: Mathematics
Topic: Word Numbers Puzzle
Replies: 33
Views: 4445

Alphabetizing a billion words (over 51 gigabytes of data) isn't even remotely challenging? This is a puzzle published by ITA to challenge computer programmers, by the way, so yes it's really a programming challenge rather than a puzzle per se. (That is, the goal isn't just to get the right answer, ...
by parallax
Wed Sep 12, 2007 6:52 pm UTC
Forum: Science
Topic: Speed of... transferrence?
Replies: 23
Views: 2600

It is exactly the same as sound.

Sound is the transfer of impulse waves through a medium.
by parallax
Wed Sep 05, 2007 1:01 pm UTC
Forum: Logic Puzzles
Topic: Buy One, Get One Free!
Replies: 30
Views: 7050

Amicitia wrote:That's trivial though, since it wouldn't make a differene except in bulk, and then you'd buy things wholesale.


He said Math professors. Trivial but logical solutions are their lifeblood.
by parallax
Tue Sep 04, 2007 8:12 pm UTC
Forum: Logic Puzzles
Topic: Buy One, Get One Free!
Replies: 30
Views: 7050

If they apply the 50% to each item, the items cost an odd amount and they round up, then you lose a couple cents compared to buy one get one free. For example, a widget costs 99c. 50% off, the widget costs 50c. Two widgets cost $1. One widget costs 99c and the second one could be free. Obviously, t...
by parallax
Tue Sep 04, 2007 7:31 pm UTC
Forum: Language/Linguistics
Topic: Punctuation and quotation (merged threads)
Replies: 79
Views: 12793

Yes, I put my punctuation where it logically goes, regardless of the formal rules of language. At least, for the sake of writing on internet message boards. If I were writing a formal paper for some reason, I would probably use the proper punctuation rules. But for now, it's "John ate a cheeseb...
by parallax
Mon Aug 27, 2007 5:52 am UTC
Forum: Forum Games
Topic: Non-Sequitur Showdown.
Replies: 4346
Views: 556098

May your nights be filled with creamy nougat.

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